christopher



A. BK CHRISTOPHER.

CALCULATOR.I

APPLICATION FILED MAI/24,1919.

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CALCULATOR. APPLICATION FILED M'AY24,1919.

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CALCULATOR.

APPLICATION FILED MAY 24, 1919.

Pafmted June 3.5, 192Go 3 SHEETS-SHEET 3.-

UNITED. STATES PATENT OFFICE.`

X ARTHUR B. CHRISTOPHER, OF ST. LOUIS, MISSOURI, ASSIGNORv TO THE MEASURE- GRAPH COMPANY, OF S'll. LOUIS, MISSOURI, A CORPORATION.

CALCULATOR. A

Application filed May 24, 1919. Serial No- 299,579.

l To all whom t may concern:

Be it known that I, ARTHUR B. CHRis'ro- PHER, a citizen of the United States, residing in the city of St. Louis and State of Missouri, have provements in Calculators, of which the following is a specification. l

This invention relates to a calculator, and particularly to that typeof calculator which comprises a plurality of calculating drums which are mounted so that any one of the drums may be presented in the position to be read.

The general object' of the invention is to produce a calculator of this type in which the drums are at all ltimes completely enveloped by the case, the parts being so or-` ganized, and the case so constructed as to enable-the drums to be rotated on their individual axes by means which can be operated from the exterior of the case when the drum which is being used` is in the reading position. The different drums carry calculating tables having a different range; or each drum may carry calculating tables for making different kinds of computations. The invention provides for enabling the index number of each drum to be visible in substantially any position a drum may assume. In this way, I produce a very compact calculating device which is particularly useful for making computations upon different rates such as computing the wages of workmen at dierent rates per hour or for making any other computations where different rates are used as a multiplier. v

The invention consists in the novel features, and in the general combination of parts hereinafterdescribed, all of which contribute to produce a simple and efficient calculator. A preferred embodiment of my invention will be particularly described in the following specification, while the broad scope of my invention will be pointed out in the appended claims.

In the drawing, which fully illustrates a preferred embodiment of my invention,

Figure 1 is a plan of the calculator;

Fig. 2 is a side elevations;

Fig. 3 is an end elevation;

Fig. 4 is a vertical cross-section taken at one end of the machine, certain parts being broken away;

Fig. 5 is a perspectiveof one of the computing strips such as carried by the drums;

invented new and useful Im- Fig. 6 is a side elevation, broken away, of a holder which may be employed for removably holding the computing strips on the drums;

Fig. 7 is an end elevation of the stripholder shown in Fig. 6;

Fig. 8 is a longitudinally vertical section through the device; and

Fig. 9 is a fragmentary perspective of one end of the ca se of' themachine.

In practising my invention, I provide a plurality of individually rotatable calculating drums which are disposed circumferentially about a central axis; these drums carry calculating tables on their faces. I also provide a case which completely envelops the drums in any position they may assume, and this case is provided with a sight-opening at the point where the drums are positioned in order to be read, that is to say, at the point where the 'tables on the drums are visible through the sight-opening. Associated with i each drum, I provide means for rotating it on l its individual axis so as to bring thefdifferent tables on the drum into alinement with the siglit-opening; the case is so constructed as to render this rotating means accessible from the exterior of the case when its corresponding druin is in its reading position.

In order to accomplish these results, I provide a plurality of calculating drums 1 which are arranged parallel to each other,

and with their axes disposed circumferentially about a central horizontal axis.v I provide means for supporting and for rotating these drums around the central axis, comprising a central shaft 2 near the ends of which, disks or heads 3 are ri 'dly attached to bushings 4 carried rigid on the shaft. On the faces of the drums, Iyprovide a plurality of longitudinally extending computing strips 5, one of which is illustrated in Fig. 5. These strips may be formed of celluloid or paper, and are provided with divisions progressively numbered, for example, 20, 30, 40, 50, etc.

In order to hold these strips conveniently on the faces of the drums, I provide a holder corresponding to each strip, which is simply in the form of a strip of metal extending longitudinally on the faces of the drum having upwardly and inwardly bent ianges 7, the strips being inserted in the holders by shoving them longitudinally into the holders from one' end. As illustrated in Figs.

6 and 7, the body 8 of the holder is represented as flat, but it should be understood that this metal is very light, and the body 8 of each strip will assume theconveX form of the drum`when attached to the drum as illustrated in Fig. 4. i 'Ii provide means associated with each drum for rotating it upon its individual axis, consisting of a pin 9 fixed in the end of the drum and operating as a pivot passing through one of the heads or disks 3, the outer end of each of these pinsbeing pro, vided with a thiunb-head 10. AI provide each drum with a plurality of thecomputing strips 5, forexample six strips. This will rive considerable range for the instrument. Iilvidently by rotatingthe thumb-head 10, its corresponding drum maybe rotated so as to bring any strip into the desired position. The ends of the drums opposite to the pins 9 are rotatably supported in the opposite head 3 on central pins 11.

Any suitable means may be provided for holding the drums in any position in which they are left. For this purpose, I may provide each pin 9 with a rigidly attached starwheel 12, with which coperates a resilient detent 13, secured on the inner face of the adjacent head 3, see- Figs. 4 and 8. This star-wheel 12 has as many notches as there are strips on the drum. When the drum is stationary on its axis, the detent 13 occupies one of these notches and holds the` drum against accidental rotation.

The drums are completely enveloped in any position they may assume, by a case 14: which may be formed of light sheet metal, presenting a cylindrical upper portion or, dome 14a, said case seating upon and being attached to a base-plate or board 15. The rear end wall 16 of this case may be] formed of wood provided with a bushing` 17 for rotatably supporting the outer end of the central shaft 2. 1

In order to enable the thumb-heads 10 to be accessible from the-exterior of the case to enable any drum to be rotated when it is at the reading position, I provide the end wall of the case with a slot.4 This slot is preferably of arcuate form'and lthe thumbheads 10 simply project' through the slot, see Fig. 8.

In the present instance, I construct the end 'wall 18 with an inwardly offset upper portion 19, and an outwardly offset lower portion 20, said portions 19 and 20 being inn tegrally connected .by a horizontal extension 21. In other words, I simply form the end wall 18 of a vertical plate pressed so as to present a jog or horizontal offset. In the lower portion 20 of the end wall 18, the shaft 2 is rotatably mounted, passing through a suitable bushing 22, and on the exterior of the case, this shaft is provided with a suitable knob 23 for rotating the shaft 2, thereby enabling the operator of the instrument to bring any drum to the reading position.

vIn order toV enable the thumb-heads to pass up from the lower portion of the case, the horizontal extension 21 isA formed with a notch or slot 25 which connects with the slot 24a-'see Fi 9. l

I provide t e end faces 26 of the thumbheads, with index numbers indicating the range of the tables corresponding to that drum, see Fig. 3, and in order to enable these index numbers to be visible in substantially all positions the drums may assume, I provide the lower portion 2O of the end wall 18 with an arcuate slot 27.'

The reading position, that is to say, the point at which the tables of the drums are visible, is preferably located directly over the shaft 2, at the highest point on the domo 14, and at this point, I- provide a sightopening 28 which may be covered by a glass strip or window 29. Adjacent this point, the case is formed with undercut slots 30 which receive two scales 31 and 32, the scale 31 having divisions progressively numbered to represent units of any kind, for example, hours. The opposite scale 32 maybe provided with progressively numbered divisions corresponding to half hours.

The case is also formed so as to present a longitudinally extending guideway 33 carrying a movable slide or runner 34. This slide 34 is simply a bar having a slot 35 which extends transversely across the sight-opening 28 and the two scales 31 and 32. In Fig. 1, the computing scale which is in the reading position, that is to say, under the window 29, represents a rate of 20c per hour. The numbers 'on this scale aline with the numbers on the scales 31 and 32 and are functions of the unit rate and the numbers on these scales, for example, the figure on the computing scale opposite the third hour is 60, indicating that at the rate of 2095 per hour the total for the three hours will be 60c. To prevent errors, the slide or runner 34 should be moved to the point on the scale where the reading is to be taken, for example, in Fig. 1, the slide is placed at the fourteenth hour, and the computing scale indicates 280, that is to say, $2.80 which should be the total for this rate.

It should be understood that the scale shown in Fig. 1 is so simple, that the computation could easily be made mentally, but in actual practice, the rate might include a fractional number, so that the computations might not always be so simple.

`In order to hold any given drum in position at the reading point any suitable detent device may be employed, for example, this detent device may be similar to that described for detainincr the drums against rotation on their individual axes, that is to say, I provide the shaft 2 near one end with a ri id star-Wheel 36 having a number of notc es 37 corresponding to the number of drums carried in. the instrument, and co operating with the notches, I provide a detent 38 which is pressed by` a coil spring 39 so as to hold the detent in engagement with the star-wheel.l This will give thev shaft 2 a step-by-step movement when it is rotated.

In the mode of operation of the machine, the operator examines the index numbers on the end faces of the thumb-heads to ascertain the present position of the drum which he desires to emplo in the computation about to be made. ltle then seizes the knob 23 and rotatesthe shaft, 2 so as to carry the Adesired drum up to the readingposition.

After the drum arrives at the reading position its thumb-head 10 is then, rotated until the desired scale of that drum is presented under the sight-opening. The slot 34 is then slid to the proper'point and the readin taken 0E of the drum.

t is understood that the embodiment of vthe invention described hereinabove, is only one of the many embodiments the invention may take, and I do not wish to be limited in the practice of my invention nor in my glaiglis, to the particular embodiment set ort What I claim and desire to secure by Let-- ters Patent is r 1. In a calculator,vthe combinatibn of a plurality of individually rotatable calculating drums disposed circumferentially about a central axis, said drums having calculating tables on their 7faces, a case having a sight-opening, means for supporting and for rotating said drums about said central axis to bring any of the drums into position opposite said sight-opening, said'caseenveloping all of said drums 1n any position the drums may assume, and means associated with each drum for rotatingthe same upon its individual axis, said last named means lying outside ofthe vcase when the drum carried thereby lies vopposite said Asightopenmg. f

2. In a` calculator, the combination of a plurality o`f individually rotatable calculating drums disposed circunrferentially about a central axis, said drums having calculating tables on their faces, a case having a sight-opening, means for supporting and for rotating said drums about said central axis to bring any of the drums into position opposite sa1d sight-o ening,l said case e11- veloping all of said ruins in any position the drums may assume, a member associated with each drum for rotating thesame upon its individual axis, the wall of said case having an opening through which said last named member projects when its corresponding drum lies opposite said sightopening. i

3. In a calculator, the combination of aplurality of individually rotatable calculat- "ing drums disposed circumferentially about head associated with each drum for rotating the same upon its individual axis, said case having an end wall with an inwardly offset upper portion having a slotV therein along which each thumb-head passes, and through which each thumb-head projects when its corresponding drum lies opposite said sightopening. j

4. In a calculator, the combination of a plurality of individually rotatable calculating drums disposed circumferentially about a central axis, said drums having calculating tables on their faces, a case having a sight-opening, means for supporting and for rotating said drums about said central axis to bring any of the drums into position opposite said sight-opening, said case enveloping all Kof said drums 1n any position the drums may assume, a member carried by each drum for rotating the same upon its individual axis, said case having an end wall with an inwardly offset upper portion having a slot therein through which said last named member projects when its corresponding drum lies opposite said sightopening, said end wall having an outwardly offset portion with-an opening therethrough, through which the ends lof said members are visible, the ends of said members bearing numbers indicating the range of the calculating tables carried by the corresponding drum. t

5. In a calculator, the combination of a plurality of individually rotatable calculating drums disposed circumferentially about a central axis, said drums having calculatf ing tables on their faces, a case having a sight-opening, means for supporting and for rotating said drums about said central axisv to bring any of the drums into position opposite said sight-opening, said case enveloping all of'said drums in any'position the drums may assume a thumb-head assocated with yeach drum for rotating the same upon its individualtaxis, said case having an end Wall with a slot. therethrough, along which each thumb-head passes, and through which each thumb-head projects when its corresponding drum lies opposite said sightopening. v

6. In a calculator, the combination of a plurality of individually rotatable calculatlng drums disposed circumferentially about a central axis, said drums having4 calculat- YV13o ing tables on their faces, a case having a sight-opening, means for supporting and for rotating said drums about said central axis to bring any of the drums into position opposite said sight-opening, said case enveloping all of said drums in any position the drums may assume, a thumb-head carried by each drum for rotating the same iipon its individual aXissaid case having an end Wall With an invvfardlyl ofset upper portion having a slot therein and having an voutwardly offset lower portion, said olfset portionsl being connected b a substantiall horizontal extension of sai Wall, said horizontal extension having a slot communicating With said first named slot through which the said thumb-head of each drum passes when the drum moves toward said sightopening.

In testimony whereof I have hereunto set my hand.

ARTHUR B. CHRISTOPHER. 

